Koekotroides tewhaarua, J.-P & Myers & Shepherd, 2025

J. - P, Olivier, Myers, Alan A. & Shepherd, Lara D., 2025, A new genus and six new species of endemic landhopper in the family Arcitalitridae (Amphipoda: Talitroidea) from New Zealand, Zootaxa 5691 (2), pp. 277-311 : 290-292

Koekotroides tewhaarua sp. nov.

( Figs 8–10 )

Genus A sp. 3 ( Ball et al. 2024).

Type material. Holotype: female ( MNZ CR.027738 ), body length 5.5 mm, Tasman Valley along Tasman Stream , Great Island, Three Kings Islands, Northland, New Zealand, native forest, sifting leaf litter and rotten wood, coll. Buckley T.R., Leschen R.A.B., 10 November 2008 . Allotype: male ( MNZ CR.027737 ), body length 5.0 mm, same data as holotype. Paratypes: 2 females (body lengths 6.0– 6.5 mm), 1 male (body length 6.0 mm), 2 juveniles (body lengths 5.0 mm) ( MNZ CR.027736 ), same data as holotype .

Etymology. Te whārua is a valley hollow or depression, referring to the concavities and depressions of epimeron 3. As well as representing concavities, depressions, valleys and hollows, Whāwhārua also represents descent from a female ancestor in the whakapapa (genealogy). Te whārua, a mokopuna (grandchild) of Papatūānuku (our Earthmother) creates everlasting symbiotic relationships within our ecosystem that lead to maintaining a healthy and thriving environment. Te whaarua, the valleys of life, where natural features are created by the embracing energies of Papatūānuku (Earth mother) and Ranginui (Sky father) to bring forth a complementary state of balance in our environment and in humanity. From the mountains to the valleys to the rivers to the oceans, te waiora (waters of life), flow unceasingly through the channels of te whaarua.

Description. Adult female 5.0–7.0 mm.

Head. Antenna 1 extending to at least half of the way along peduncle article 5 of antenna 2; article 3 of peduncle longer than article 2; flagellum consisting of 4–5 articles. Antenna 2 article 4 length 2.5–2.7 times breadth; article 5, 1.5 times length of article 4; flagellum subequal in length to peduncle, consisting of about 11–14 articles. Maxilliped compact, not splayed; endopodite apex rounded; exopodite distally arcuate with blunt apex; palp article 2 without distomedial lobe; article 4 small but distinct.

Pereon. Gnathopod 1 coxa sub-trapezoidal, anterior margin weakly sinuate to nearly straight; basis anterior margin weakly concave proximally; merus posterior margin without lobe covered in palmate setae; carpus elongate, posterior margin evenly convex, without lobe covered in palmate setae; propodus, about 0.6–0.7 times length of carpus, semi-elliptical, posterior margin with 4, (exceptionally 5) long, straight, spear-like robust setae, palm oblique, simple. Gnathopod 2 slender, basis 3 times as long as broad; merus produced posterodistally into a lobe covered in palmate setae; carpus and propodus short, stout, carpus posterior margin with lobe covered in palmate setae; propodus mitten-shaped in both sexes (femipod), slightly longer than carpus, distal lobe apically rounded, covered in palmate setae; dactylus very short. Pereopod 3–4 parallel-sided in lateral view, anterior margin concave distally in frontal view; ischium short; merus long; carpus 0.6 times length of merus; propodus distinctly longer than carpus. Pereopod 5 basis evenly narrowing distally, anterior margin weakly convex, posterior margin convex proximally; carpus and merus subequal in length; propodus approximately 1.2 times longer than carpus. Pereopod 6 basis sub-elliptical, slightly narrower distally, margins convex; carpus subequal in length to merus; propodus approximately 1.3 times length of carpus. Pereopod 7 basis broadly obovate, nearly, as broad as long, posterior margin with small serrations each with a small seta; merus, carpus and propodus each progressively a little longer than the preceding article.

Pleon. Epimeron 1 shortest, posterior margin nearly straight; posteroventral corner with or without a small, subacute or rounded process. Epimeron 2 ventral margin weakly convex to nearly straight, deepest posteriorly; posteroventral corner nearly a right angle, with or without small, subacute or rounded process; posterior margin weakly convex to nearly straight, with small serrations or crenulations, each with a very fine seta. Epimeron 3 as deep as epimeron 2 at anteroventral corner; ventral margin very convex anteriorly, distinctly concave posteriorly; posteroventral corner usually with strong blunt or subacute process; posterior margin distinctly crenulate, convex. Pleopods 1–3 biramous; exopodites usually slightly shorter than endopodites, often much shorter in pleopod 3. Pleopod 1 longest; endopodite 0.4 times length of peduncle. Pleopod 2 shorter than pleopod 1; endopodite 0.4 times length of peduncle. Pleopod 3 shortest and narrowest; endopodite 0.4 times length of peduncle. Uropod 1 peduncle longer than the subequal rami, outer margin with 2 dorsal robust setae distally; distolateral robust seta approximately 0.5 times length of exopodite; exopodite without dorsal robust setae; endopodite with 1–2 (sometimes 3) dorsal robust setae. Uropod 2 peduncle subequal in length with endopodite; endopodite longer and stouter than exopodite with 2 marginal robust setae; exopodite without marginal robust setae. Uropod 3 peduncle bulbous, with 1 very long lateral robust seta; ramus approximately 0.3 times length of peduncle, with 1 apical seta. Telson as broad as long, undulate, not incised apically, deep longitudinal furrow present ventrally, 1 large apical robust seta and 2 large dorsal robust setae on each side.

Habitat. Native forest.

Distribution. Three Kings Islands (Manawatāwhi/Great Island, Oromaki/North East Island).

Remarks. Koekotroides tewhaarua sp. nov. is most closely related to K. maene sp. nov. but differs from it most obviously in the crenulate posterior margin of epimeron 3 (smooth in K. maene sp. nov.).

Figures

FIGURE 8. Koekotroides tewhaarua sp. nov., female paratype (antennae, maxilliped (including detail of palp article 4), pleopods 1–3, epimera 2–3, uropods 1–3, telson), Manawatāwhi, Three Kings Islands. Scale bars a = maxilliped; b = epimera, uropods 1–2; c = uropod 3, telson; d = antennae; e = pleopods.

FIGURE 9. Koekotroides tewhaarua sp. nov., female paratype (gnathopod 1 (detail of propodus), gnathopod 2), Manawatāwhi, Three Kings Islands.

FIGURE 10. Koekotroides tewhaarua sp. nov., female paratype (pereopods 3–7, oostegite on pereopod 4), Manawatāwhi, Three Kings Islands.